Looking at the habits of nearly 10,000 teenagers from Norway aged 16-19, the study found a strong link between the amount of time looking at a screen (smartphone, computer, TV or tablet) and quality of sleep.
More than two hours spent looking at screens after school was found to cause both delayed and shorter sleep. Almost all of the participants of the study admitted to using electronic devices shortly before going to bed.
The participants were asked about their sleep routines on weekdays and weekends, and how much screen time they indulged in outside of school hours.
It was found that, on average, girls clocked up about five and a half hours a day looking at screens, while boys clocked up around six and a half. Girls tended to spend more time chatting online, while boys were more likely to play video games.
When screen use for the day totalled four or more hours, the teens had a 49% greater risk of taking longer to get to sleep. These teens were also found to only get five hours of sleep or less.
The researchers from Uni Research Health, Bergen say it could be that playing on electrical devices is leaving teens less time to do other things – including sleep.
It could also be that looking at illuminated screens in the evening sends the wrong signals to the brain, disrupting our natural body clock and making us feel more alert. Lead researcher of the study, Dr Mari Hysing said these findings have implications for the wider population and not just teens,
“We know that sufficient sleep is essential for good physical and mental health. Logging off may be one important step toward securing a good night’s sleep.”
Prof Russell Foster, an expert in sleep at the University of Oxford said that the study is important as it provides clear evidence that the use of electronic devices before bed does reduce sleep duration.